Safety and efficacy of h1-antihistamines plus ranitidine in refractory Chronic Spontaneous Urticaria

Background Some patients with chronic spontaneous urticaria (CSU) remain inadequately controlled despite receiving double doses of H1-antihistamines (H1-AH). The high cost of omalizumab, coupled with the risk of allergic reactions in some patients, highlights the need for alternative treatment options for these refractory cases. Objective This study aimed to assess the efficacy and safety of adding H1-AH plus ranitidine to the original treatment in a subset of patients with refractory urticaria. Methods This was a randomized, open-label study involving patients with CSU that remained uncontrolled after ≥ 2 weeks of double-dose H1-AH therapy. The primary endpoints were the Weekly Urticaria Activity Score (UAS7) response (score < 7) and the Urticaria Control Test (UCT) response (score ≥ 12) at week 12. Results A total of 33 patients with refractory CSU were enrolled in this study. At week 12, 16 patients (48%) achieved a UAS7 response (score < 7), while 15 patients (45%) attained disease control (UCT ≥ 12). Overall, 21 patients (64%) showed an improvement of ≥ 5 points in the Weekly Itch Severity Score (ISS7). There were also significantly greater improvements in the Dermatology Life Quality Index (DLQI) (-2). Regarding adverse reactions, the treatment was well tolerated. A total of 4 (12%) patients experiencing AEs after the addition of ranitidine. Conclusions In refractory CSU patients with the following characteristics: short disease duration, baseline UAS7 score < 25, wheal-type skin lesions without excoriations, negative autologous serum skin test (ASST), or concomitant cholinergic urticaria, ranitidine add-on therapy may improve treatment response rates.